Endosymbiotic Theory

What happened to the membrane bound organelles that were present in the eukaryote that gulped the primary endosymbiont (that is, the eukaryote that gulped a prokaryote), after the secondary endosymbiosis.

Its not clear these cells were, but here is a recent thread about some which might have been a close relative to it.
These cells are only known from their molecules, they have not been identified and details of their structure are not yet known.
There is speculation that these pre-eukaryotes may have already had some internal membranes, but they have not yet been seen.